S5 Q Pipeline Status

1. S5 Q Pipeline Status Shourov K. Chatterji Caltech LIGO Scientific Collaboration meeting MIT 2006 November 5

2. S5 Q Pipeline search • The Q Pipeline is being applied to search for untriggered bursts in S5 data through 2006 April 3. • There are two primary components of this analysis • H1H2 double coincident search for combined excess signal energy followed by H1H2 null stream consistency test • H1H2L1 triple coincident search for time frequency coincidence between H1H2 triggers and L1 triggers • Upper limits will be determined using the loudest event statistic • The loudest N events will be followed up QScans and a fully coherent follow-up if data is available from a sufficient number of detectors LSC meeting 2006 November 5

3. Q Pipeline • Multiresolution time-frequency search for statistically significant excess signal energy • Projects whitened data onto an overlapping basis of sinusoidal Gaussians characterized by central time, central frequency, and Q (ratio of central frequency to bandwidth) • The template bank is constructed using a maximum mismatch approach similar to the matched filtering approach • The search is equivalent to a matched filter search for waveforms that are sinusoidal Gaussians after whitening • The reported normalized energy is measure of event significance and is simply twice the squared SNR that would be reported by a matched filter search LSC meeting 2006 November 5

4. H1H2 Null stream veto • The collocated H1H2 search has two components • H+: The optimal linear combination of H1 and H2 that maximizes the SNR of potential signals • Weighting factors are inversely proportional to power spectral density in each frequency bin • Normalized energy, Z+, is twice the quadrature sum of SNR in both detectors • H-: The H1 – H2 null stream, which should be consistent with noise for real gravitational-waves • To avoid calibration uncertainties, test normalized energy, Z-, against that expected null stream normalized energy, Z0, assuming incoherent glitches in the two detectors • Z- > a + b Z0 LSC meeting 2006 November 5

5. Analysis code • The QScan and QPipeline codes have been merged into a single code base, which is now available in the LSC MatApps CVS repository [links: code, documentation] • This code base is now installated on most LSC computing clusters and LIGO laboratory general computing networks. • Running QPipeline is now as simple as running QScan ssh ldas-pcdev1.ligo.caltech.edu mkdir –p ~/qpipelinetest cd ~/qpipelinetest ~shourov/qscan/bin/qpipeline.sh \ 843214931 843215031 \ @H1H2-collocated @S5 . It’s easy!Try it now! LSC meeting 2006 November 5

6. Summary of livetime and duty cycle H1 H1H2 90.1(60.1%) 3.3(2.2%) 5.1(3.4%) 34.4(22.9%) 55.8(37.2%) 12.7(8.5%) 10.2(6.8%) 7.1(4.7%) H2 L1 Livetime in days through April 3, 2006 Duty cycle relative to start of S5 at LHO LSC meeting 2006 November 5

7. Data quality and vetoes • The following data quality flags were used to define the segment lists for trigger generation • No other data quality flags have been applied. • No auxiliary channel vetoes have been applied. OUT_OF_LOCK OUT_OF_SCIENCE_MODE PRE_LOCKLOSS_120 MISSING_RDS_C02_LX Injection LSC meeting 2006 November 5

8. Search parameters channelNames: {'H1:LSC-STRAIN', 'H2:LSC-STRAIN'} frameTypes: {'H1_RDS_C02_LX', 'H2_RDS_C02_LX'} timeShifts: [+0 -1] injectionNames: {'H1:GW-H', 'H2:GW-H'} injectionTypes: {'SG2_S5_A', 'SG2_S5_A'} injectionFactors: [0.5 0.5] reSampleFrequency: 4096 blockDuration: 64 minimumBlockOverlap: 8 qRange: [4 64] frequencyRange: [64 1024] maximumMismatch: 0.2 analysisMode: 'collocated' outlierFactor: 2.0 falseRate: 1e0 maximumSignificants: 1e5 maximumTriggers: 1e3 durationInflation: 1.0 bandwidthInflation: 1.0 Using h(t) data Using burst MDCs Search space LSC meeting 2006 November 5

9. Post-processing parameters • High threshold veto • H+ events are excluded if they fall within two seconds of very inconsistent tiles (Z- > 128 + 0.1 Z0) • Low threshold veto • H+ events are excluded if they overlap inconsistent tiles (Z- > 18 + 0.05 Z0). • Low frequency, low Q cut • A significant fraction of all glitches are observed to fall in the lowest frequency, lowest Q template. • H+ events are excluded if they have a central frequency less than 100 Hz and a Q less than 14. LSC meeting 2006 November 5

10. Trigger production • Trigger production and post-processing is visible online LSC meeting 2006 November 5

11. Distribution of H1H2 significance Loudest event Z+ = 176 LSC meeting 2006 November 5

12. Loudest H1H2 event • Loudest event is low Q burst in H1 • No clear glitch in H2 • Why did this pass the H1H2 null stream veto? • Potential room for improved veto tuning? H1 H2 LSC meeting 2006 November 5

13. Efficiency for sinusoidal Gaussians LSC meeting 2006 November 5

14. Efficiency for sinusoidal Gaussians LSC meeting 2006 November 5

15. Efficiency for Gaussians LSC meeting 2006 November 5

16. Efficiency for white noise bursts LSC meeting 2006 November 5

17. Predicted (“time lag”) upper limits Decreased efficiency Increased livetime Crossover at 7e-22 and 0.08 events per day LSC meeting 2006 November 5

18. Outlook • Further tuning will likely improve performance • Anything that eliminates loud events will improve the resulting upper limit • Triple coincidence (at the expense of livetime) • Application of data quality flags and vetoes based on auxiliary or environmental channels • Concern about potential zero lag H1H2 surprise • Use S4 as a playground data set • Trigger production complete at 17 different time lags including zero lag • Use one day of S5 as a playground data set • Once tuning is complete, the box will be opened for the analysis through April 3. LSC meeting 2006 November 5